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Understanding what dark energy is, understanding what it is that's making the universe expand faster is an incredibly important thing for understanding the future of the universe.
了解什么是暗能量，什么使宇宙膨胀得更快，对于了解宇宙的未来发展是一件极其重要的事情。
Right now, the evolution of the cosmos is dominated by this mysterious dark energy that we can't see, we don't understand.
现在，这种神秘的暗能量主导着宇宙的演变，我们看不到，也不了解它。
If we figure out what it's doing, if we figure out what it's made of, how it's going to change in the future, then we will have a much better idea for how the universe will end.
如果我们清楚它的功能，清楚它是由什么组成的，它在未来将如何变化，那么我们会更加了解宇宙的最终发展。
Dark matter is very different from dark energy.
暗物质与暗能量非常不同。
People often get these two ideas confused because they're both called dark.
人们经常把这两个概念搞混，因为它们都被称为暗。
And also because there are connections between matter and energy.
另一个原因是物质和能量之间存在着联系。
People might have heard of E = mc2, this idea that there's a way to relate the mass of something to its energy, that's from Einstein.
人们可能听说过爱因斯坦的一个理论，E = mc2，即有一种方法可以将某物的质量与能量联系起来。
In this case, dark matter and dark energy don't seem to be related to each other in any way, that we know.
我们知道，暗物质和暗能量似乎没有任何关系。
They're both called dark because we cannot see them and they're mysterious.
它们都被称为黑暗，是因为我们看不到它们，它们是神秘的存在。
That's where the similarity ends.
这就是其相似之处。
Neither one is dark in the sense of being black.
但是两者都不是黑色的意义上的黑暗。
They're dark in the sense of being invisible.
它们是在看不见的意义上的黑暗。
They don't emit light, they don't absorb light, they don't reflect light.
它们不发射光，不吸收光，不反射光。
They don't seem to interact with light at all, as far as we can tell.
就我们所知，它们似乎根本和光没有任何联系。
Dark matter seems to be something that interacts via gravity so it has mass, it's matter.
暗物质似乎是通过引力相互作用产生的，所以它有质量，它是物质。
But it doesn't seem to interact via the other forces of nature in any way that we've been able to tell.
但是，我们已经知道它似乎和自然界的其他力量没有任何关联。
Dark energy only does this thing where it makes space expand, it interacts only with space.
暗能量只能使空间膨胀，它只与空间有关联。
And there's a possibility that dark energy is just a property of space that every little bit of space has a little bit of expansion built in, and as the universe gets bigger and bigger, there's more and more space, and so that expansion starts to win out over the gravity that's trying to slow it down.
有一种可能性是，暗能量只是空间的一种属性，每一点空间都有一点膨胀，随着宇宙变得越来越大，空间越来越大，所以膨胀开始胜过试图减缓它的重力。
And so, the universe starts expanding faster and faster.
因此，宇宙开始越来越快地膨胀。
That's one possibility for dark energy, that it's just a cosmological constant, it's just part of how the universe works, that it has this expansiveness built into it.
这是暗能量的一种可能性，它只是一个宇宙学常数，它只是宇宙运行方式的一部分，它有这种扩张性的内涵。
But it's possible it's something else.
但也有可能是别的东西。
It's possible that whatever is making the universe expand faster and faster is something weird and different, something that acts in a totally different way.
有可能使宇宙膨胀得越来越快的东西是一种奇怪的、不同的东西，以一种完全不同的方式行事。
That also accelerates the expansion of the universe, but maybe it changes over time in some way that we don't understand.
这也加速了宇宙的膨胀，但也许它以某种我们不了解的方式随时间变化。
One of the possibilities for that is something called phantom dark energy.
这方面的可能性之一是一种叫做幻影暗能量的东西。
Phantom dark energy would be something where dark energy is getting more powerful over time.
幻影暗能量将是暗能量随着时间的推移变得更加强大的东西。
That means that in a particular volume of space, the amount of dark energy in that volume starts growing.
这意味着在一个特定的空间体积中，该体积中的暗能量开始增长。
And that would actually lead to a total apocalypse in a relatively short time.
而这实际上会导致在相对较短的时间内出现全面的启示。
What it would do is it would start tearing apart things in the universe.
它所做的是它将开始撕裂宇宙中的事物。
If dark energy is not a cosmological constant, if it's this phantom dark energy, then the amount of dark energy is going to get higher over time.
如果暗能量不是一个宇宙学常数，如果它是这种幽灵般的暗能量，那么随着时间的推移，暗能量的数量会越来越多。
And so, the stars that have been orbiting very stably in the past will start to feel pushed out by more and more of this expansion happening inside the galaxy.
因此，过去一直非常稳定地运行的恒星将开始感到被星系内部发生的越来越多的膨胀推了出去。
So, in the scenario that dark energy is this weird stuff, this phantom dark energy, then it does start to actually pull matter apart.
因此，如果暗能量是这种奇怪的东西，这种幽灵般的暗能量，那么它确实开始将物质分离。
So it would first start to pull galaxies away from other galaxies in these giant galaxy clusters.
它首先会开始把星系从这些巨大的星系团中的其他星系拉开。
Then it would start to pull stars away from galaxies, so we'd see the stars in the Milky Way would start to drift away.
然后它将开始把恒星从星系中拉走，所以我们会看到银河系中的恒星开始漂移。
And then it would start to pull planets away from their suns.
然后，它将开始把行星拉离太阳。
And then, it would start to actually pull apart planets and stars, and even eventually atoms and particles—it would start to just rip everything apart.
它将开始真正分开行星和恒星，甚至最终分开原子和粒子--它将开始分开一切事物。
And in some, at some point in the future, it would kinda tear apart the whole universe in a process we know as The Big Rip.
在某些情况下，在未来的某个时间点，它将在一个我们称为大裂变的过程中分裂整个宇宙。
So, based on our current data, there's some uncertainty in our current measurements of the expansion of the universe.
因此，基于我们目前的数据，我们目前对宇宙膨胀的测量存在一些不确定性。
And that uncertainly leaves some space for the possibility that our universe is headed toward a Big Rip.
而这种不确定性为我们的宇宙正走向大裂变的可能性留下了一些空间。
And based on the uncertainties in the measurements, what we can say is that we're almost certain not to have a Big Rip in the next 200 billion years or so.
基于测量中的不确定性，我们可以说，我们几乎可以肯定在未来2000亿年左右不会发生大裂变。
But we can't say for sure that it will never happen.
但我们不能肯定地说，它永远不会发生。
And even as we get more and more precise measurements, all that's really going to do is push this scenario farther into the future, and say, well, maybe we'll get much better measurements in a few years, and then that'll tell us we definitely won't have a Big Rip for the next hundred thousand billion years.
即使我们得到了越来越精确的测量，所有这一切真正要做的是把这种情况推到更远的未来，并说，好吧，也许我们在几年内会得到更好的测量，然后这将告诉我们在接下来的十万亿年内我们肯定不会有大裂变。
You might, at some point, get to that, but you'll never be able to say that it'll never happen because no measurement is ever 100% complete.
你可能会在某个时候达到这个目的，但你永远无法说它永远不会发生，因为没有任何测量是100%完整的。
So unless we really understand what dark energy is, which at the moment, we don't, we can't say for certain that it won't at some point, rip the universe apart.
因此，除非我们真正了解暗能量是什么，而目前我们还不了解，我们不能肯定地说，它不会在某个时候将宇宙分裂开。
We can just say that if it's going to do that, it'll be a really long time from now.
我们只能说，如果会这样的话，也是在很久以后。
Alternatively, dark energy could be something that changes fundamentally over time, that doesn't get more powerful, but gets less powerful and actually changes direction.
另外，暗能量可能是随着时间的推移而发生根本性变化的东西，它不会变得更强大，而是变得更不强大，也改变了方向。
